Many rotating drive systems employ a speed governor or speed control device to maintain a relatively constant rotational speed. The object of such speed governors is to compensate for variations of drive power such as those caused in electrical motor drive systems due to battery fluctuations or those used in spring wound motor drive systems which tend to be relatively inconsistent.
The need for speed governors in rotational systems has prompted practitioners in the art to create and provide a variety of rotational speed governors. Perhaps one of the most successful and pervasive types of speed governor structure utilizes a rotationally supported rotor usually operating within a fixed drum or housing A plurality of weights are pivotally supported upon the rotor in a manner which causes them to pivot and extend outwardly in response to centrifugal forces caused by rotor rotation. In most speed governors, a weight return or counterforce spring is coupled to the pivotally supported weights in a manner urging the weights inwardly upon the rotor in opposition to the outward force caused by centrifugal force. The interior surface of the stationary drum is usually adapted to provide a frictional force against the counterweights as they extend outwardly in response to centrifugal forces as the rotors turns. As the rotors turns faster, the centrifugal force overcomes the return spring force and pivots the weights outwardly. The resisting spring force is chosen such that the centrifugal force at the maximum desired rotational speed is sufficient to force the outer surfaces of the counterweights against the interior surface of the stationary drum thereby producing a resisting force which controls the rotor speed. In the event speed decreases, a correspondingly reduced centrifugal force is applied to the counterweights which permits the return spring force to draw the weights inwardly.
U.S. Pat. No. 4,158,307 issued to Schwager sets forth a GOVERNOR ROTOR ASSEMBLY having a one-piece rotor which includes a base portion generally perpendicular to the axis of rotation. A pair of diametrically opposed tangentially extending U-shaped recesses are formed in the base member to receive a pair of counterweights in a pivotal attachment. A pair of torsion springs are coupled to a each of the counterweights to provide a restoring force urging the counterweights to pivot inwardly. The outer surfaces of the counterweights support a frictional material. The entire rotor assembly is received within a drum housing which provides an interior cylindrical surface which the outer surfaces of the counterweights contact as the weights move outwardly under the urging of centrifugal force.
U.S. Pat. No. 2,808,905 issued to Bohl sets forth a SPEED GOVERNOR in which a cylindrical drum housing receives and supports a rotor having a generally planar base portion. A pair of pivotally secured counterweights are supported upon the base portion and define outer break surfaces adapted to frictionally engage the interior drum surface of the housing. The pivotal attachment of the counterweights is intermediate the inner and outer ends thereof and a return spring is coupled between the outwardly extending end portions of the counterweights. A spacing member is supported upon the base portion between the inwardly extending ends of the counterweights to provide a spacing limit therebetween.
U.S. Pat. No. 3,763,969 issued to Summerfield sets forth a SIMPLIFIED GOVERNOR in which a pull string motor driven sound producing device includes a speed governor having a shaft rotatably mounted within a housing and a weight pivotally mounted upon the shaft such that the ends of the weight are capable of moving outwardly against the housing to slow the shaft rotation. A leaf spring biases the weight inwardly out of engagement.
U.S. Pat. No. 2,513,798 issued to Hatfield sets forth a CENTRIFUGAL CLUTCH in which a drive pulley is coupled to a source of rotational power. The pulley is rotatable within a driven pulley and includes an elongated curved clutch member which is interposed between the drive pulley and the driven pulley. A combination of an eccentric weight and coupling spring controls the gripping force of the clutch in response to centrifugal forces.
U.S. Pat. No. 3,080,020 issued to Hershey sets forth a CENTRIFUGAL GOVERNOR in which a rotating shaft is coupled to a first portion having a pair of diametrically opposed outwardly extending lobes. A movable member is coupled to the lobe portion and a pair of centrifugal weights are pivotally supported on either side of the movable member. The angular displacement between the movable member and the lobed portion is controlled by the weight position which in turn is responsive to centrifugal force during shaft rotation.
U.S. Pat. No. 3,035,665 issued to Gauley sets forth a DECELERATION RESPONSIVE BRAKE having a rotatably member, a stationary member and a plurality of engaging elements pivotally mounted on the rotational member. The engaging elements are disposed with their centers of gravity between the pivotal mounting means thereof and the center of rotation of the rotatable member. Rotation of the engaging elements about the pivotal mounting axis causes the engaging elements to frictionally engage the stationary member.
U.S. Pat. No. 3,223,208 issued to Ryan, et al. sets forth a GOVERNOR having a rotatable mounted rotor and two weights rotatably mounted thereon. Between the weights, an interlocking means for equalizing the forces exerted thereon and spring means for biasing the weights inwardly is provided. The rotating member moves within a cylindrical drum having a cylindrical interior surface against which the weights engage.
U.S. Pat. No. 3,245,688 issued to Ryan sets forth a SPEAKING DOLL WITH PHONOGRAPH DEVICE THEREFOR having a phonograph device supporting a rotatable record and drive mechanism therefor. A speed governor is coupled to the rotatable drive mechanism and includes a rotor having a pair of pivotally supported counterweights which extend outwardly during rotation and engage braking surfaces to control rotational speed.
U.S. Pat. No. 3,645,363 issued to Fuths sets forth a SPEED REGULATING DEVICE in which a rotating shaft includes a base member supporting a pair of pivotally supported counterweights. The rotor and counterweights are rotatably supported within a drum member having an interior brake surface which is engaged by the counterweight at high rotation speeds.
U.S. Pat. No. 3,779,355 issued to Okuno sets forth an CENTRIFUGAL CLUTCH in which a pair of brackets are mounted on opposite ends of a clutch boss and each formed with guide projections and saddle-like arcuate shoes which in turn support friction lining material. The arcuate members are rotated outwardly in response to centrifugal force to provide frictional of a surrounding drum surface.
U.S. Pat. No. 4,015,696 issued to Lichti sets forth a CENTRIFUGAL BRAKING DEVICE having a centrifugal body pivotally connected to a sprocket and movable from a rest position to a stop position to provide breaking movement of a rotary shaft in response to rotary speed or speed changes of the shaft.
U.S. Pat. No. 4,572,333 issued to Westley sets forth a SPEED GOVERNING AND DECOUPLING DRIVE MECHANISM intended for use with a stepper motor. The mechanism includes a pinion assembly in the drive train which is rotatably coupled to the rotor by dogs on the assembly which engage spokes in a rotor in the motor when the assembly is in a first position along the axis of the rotor. The pinion assembly also includes weighted shoe which move outwardly when the assembly rotates at a speed beyond a predetermined speed to frictionally engage an internal drum surface and control rotational speed.
While the foregoing described prior art devices have provided workable speed governors for many applications, they are often expensive to fabricate and complex to assemble. Accordingly, there remains a need in the art for evermore improved speed governors which operate effectively and which are relatively inexpensive to manufacture and easy to assemble.